scholarly journals Correcting for peculiar velocities of Type Ia supernovae in clusters of galaxies

2018 ◽  
Vol 615 ◽  
pp. A162 ◽  
Author(s):  
P.-F. Léget ◽  
M. V. Pruzhinskaya ◽  
A. Ciulli ◽  
E. Gangler ◽  
G. Aldering ◽  
...  

Context. Type Ia supernovae (SNe Ia) are widely used to measure the expansion of the Universe. To perform such measurements the luminosity and cosmological redshift (z) of the SNe Ia have to be determined. The uncertainty on z includes an unknown peculiar velocity, which can be very large for SNe Ia in the virialized cores of massive clusters. Aims. We determine which SNe Ia exploded in galaxy clusters using 145 SNe Ia from the Nearby Supernova Factory. We then study how the correction for peculiar velocities of host galaxies inside the clusters improves the Hubble residuals. Methods. We found 11 candidates for membership in clusters. We applied the biweight technique to estimate the redshift of a cluster. Then, we used the galaxy cluster redshift instead of the host galaxy redshift to construct the Hubble diagram. Results. For SNe Ia inside galaxy clusters, the dispersion around the Hubble diagram when peculiar velocities are taken into account is smaller compared with a case without peculiar velocity correction, which has a wRMS = 0.130 ± 0.038 mag instead of wRMS = 0.137 ± 0.036 mag. The significance of this improvement is 3.58σ. If we remove the very nearby Virgo cluster member SN2006X (z < 0.01) from the analysis, the significance decreases to 1.34σ. The peculiar velocity correction is found to be highest for the SNe Ia hosted by blue spiral galaxies. Those SNe Ia have high local specific star formation rates and smaller stellar masses, which is seemingly counter to what might be expected given the heavy concentration of old, massive elliptical galaxies in clusters. Conclusions. As expected, the Hubble residuals of SNe Ia associated with massive galaxy clusters improve when the cluster redshift is taken as the cosmological redshift of the supernova. This fact has to be taken into account in future cosmological analyses in order to achieve higher accuracy for cosmological redshift measurements. We provide an approach to do so.

2005 ◽  
Vol 192 ◽  
pp. 525-533
Author(s):  
Weidong Li ◽  
Alexei V. Filippenko

SummaryObservations of Type Ia supernovae (SNe Ia) reveal correlations between their luminosities and light-curve shapes, and between their spectral sequence and photometric sequence. Assuming SNe Ia do not evolve at different redshifts, the Hubble diagram of SNe Ia may indicate an accelerating Universe, the signature of a cosmological constant or other forms of dark energy. Several studies raise concerns about the evolution of SNe Ia (e.g., the peculiarity rate, the rise time, and the color of SNe Ia at different redshifts), but all these studies suffer from the difficulties of obtaining high-quality spectroscopy and photometry for SNe Ia at high redshifts. There are also some troubling cases of SNe Ia that provide counter examples to the observed correlations, suggesting that a secondary parameter is necessary to describe the whole SN Ia family. Understanding SNe Ia both observationally and theoretically will be the key to boosting confidence in the SN Ia cosmological results.


2011 ◽  
Vol 732 (2) ◽  
pp. 65 ◽  
Author(s):  
Anja Weyant ◽  
Michael Wood-Vasey ◽  
Larry Wasserman ◽  
Peter Freeman

1992 ◽  
Vol 103 ◽  
pp. 379 ◽  
Author(s):  
Douglas L. Miller ◽  
David Branch

2007 ◽  
Vol 661 (2) ◽  
pp. L123-L126 ◽  
Author(s):  
James D. Neill ◽  
Michael J. Hudson ◽  
Alex Conley

2020 ◽  
Vol 499 (4) ◽  
pp. 5121-5135
Author(s):  
M V Pruzhinskaya ◽  
A K Novinskaya ◽  
N Pauna ◽  
P Rosnet

ABSTRACT Type Ia Supernovae (SNe Ia) are widely used to measure distances in the Universe. Despite the recent progress achieved in SN Ia standardization, the Hubble diagram still shows some remaining intrinsic dispersion. The remaining scatter in supernova luminosity could be due to the environmental effects that are accounted for as mass step correction in the current cosmological analyses. In this work, we compare the local and global colour (U − V), the local star formation rate, and the host stellar mass to the host galaxy morphology. The observed trends suggest that the host galaxy morphology is a relevant parameter to characterize the SN Ia environment. Therefore, we study the influence of host galaxy morphology on light-curve parameters of SNe Ia from the pantheon cosmological supernova sample. We determine the Hubble morphological type of host galaxies for a subsample of 330 SNe Ia. We confirm that the salt2 stretch parameter x1 depends on the host morphology with the p-value ∼10−14. The supernovae with lower stretch value are hosted mainly by elliptical and lenticular galaxies. No correlation for the salt2 colour parameter c is found. We also examine Hubble diagram residuals for supernovae hosted by ‘early-type’ and ‘late-type’ morphological groups of galaxies. The analysis reveals that the mean distance modulus residual in early-type galaxies is smaller than the one in late-type galaxies, which means that early-type galaxies contain brighter supernovae after stretch and colour corrections. However, we do not observe any difference in the residual dispersion for these two morphological groups. The obtained results are in the line with other analyses showing environmental dependence of SN Ia light-curve parameters and luminosity. We confirm the importance of including a host galaxy parameter into the standardization procedure of SNe Ia for further cosmological studies.


1995 ◽  
Vol 109 ◽  
pp. 1 ◽  
Author(s):  
Mario Hamuy ◽  
M. M. Phillips ◽  
Jose Maza ◽  
Nicholas B. Suntzeff ◽  
R. A. Schommer ◽  
...  

2010 ◽  
Vol 715 (2) ◽  
pp. 1021-1035 ◽  
Author(s):  
Benjamin Dilday ◽  
Bruce Bassett ◽  
Andrew Becker ◽  
Ralf Bender ◽  
Francisco Castander ◽  
...  

2018 ◽  
Vol 131 (995) ◽  
pp. 014001 ◽  
Author(s):  
M. M. Phillips ◽  
Carlos Contreras ◽  
E. Y. Hsiao ◽  
Nidia Morrell ◽  
Christopher R. Burns ◽  
...  

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